The present invention relates generally to gauging or sorting articles of manufacture, and more specifically to a method and device for sorting rivets or similar articles with headed shanks according to shank condition.
When an automatic riveter is utilized to assemble components, the rivets used therein must be uniform in size and shape so the machine will not jam or clog and so the connections formed by the rivets will be sound. The shanks of the rivets often carry oxidation or debris as a result of the annealing process which they undergo during manufacture, and it is not uncommon for shanks to be bent, gouged, burred, non-round, or swaged at the end. These and other similar non-uniformities often cause the riveting machine to jam or result in an inferior riveted connection and thus an inferior assembled product.
Various methods and devices presently available will sort articles with headed shanks according to shank length, and some sort according to shank diameter at a particular axial location on the shank. For example, a vibratory bowl qualifier checks the diameter of the rivet in only one place, thereby allowing bent rivets, burred rivets, and rivets with foreign material deposits on them to pass through. Heretofore, none of the methods and devices for sorting have been entirely successful in detecting and sorting out those articles which have non-uniformities other than completely oversized shanks or shanks which are oversized at the gauging location. Presently available methods and devices do not reliably detect burrs, gouges, swaged ends, bent or non-round shanks, or oxidation or debris.
It is therefore an object of the present invention to provide an improved method and apparatus for sorting articles with headed shanks such as rivets.
It is another object of the invention to provide an automated method of reliably sorting out non-uniform rivets or the like from a batch of rivets and directing the uniform rivets to a feeder of an automatic riveting machine, and to provide an inexpensive and yet reliable sorting machine therefor.
It is still another object of the invention to provide a method and apparatus for automatically gauging rivets and reliably rejecting rivets with oversized, bent, or burred shanks. It is a further object to provide an automatic rivet gauging apparatus which is very reliable and yet has relatively few moving parts.
The sorter is fed from a vibratory bowl sorter. Each rivet is directed in turn down a track and settles in a notch at the lower end of the track. A roller mounted on a rockable arm member retains the rivet in the notch and biases the shank against the rim of a rotating wheel. A groove or guide tapering radially inwardly from the rim of the wheel terminates in a shank-receiving gauge hole in the wheel conforming generally to the desired shape of the shanks. As the wheel rotates, the rivet is held in the groove and as the gauge hole in the wheel passes by the rivet, the rivet shank slides down the groove and enters the hole in the wheel. The rivet is carried past an air-operated rivet ejection cylinder. A cam located on the wheel operates an air switch which triggers the air cylinder. Any rivet which does not fully enter the gauge hole will be exposed to a rivet kicker on the ejection cylinder and will be ejected from the wheel into a chute for defective rivets. Acceptable rivets are carried in the wheel past the ejection cylinder to a point where an air hole in the side of the wheel aligns with an air supply hole, thereby acting as a rotary valve which passes air into the gauge hole. The air blows the acceptable rivet into a barrel where a continuous charge of air removes the rivets to a hopper adjacent the riveting machine. Therefore, rivets with shanks which are irregular will be ejected from the wheel and prevented from entering the hopper of the riveter so that the riveter operates more effectively and so that incidences of poor connections resulting from irregular rivets are reduced.
These and other objects, features, and advantages will become apparent to one skilled in the art upon reading the following detailed description taken with the drawings.